For various economic and business reasons enterprises are increasingly centralizing their backend computer systems in purpose built data centers. Data centers typically house high concentrations and densities of such computer systems and additionally provide facilities such as uninterruptible power supplies and cooling systems necessary for the operation of the computer systems in the data center.
Computer systems inherently generate heat during operation. Typical heat generating sources in a computer system include central processing units (CPUs), graphics cards, mechanical storage drives, power supplies, and the like. This heat needs to be managed such that the maximum operating temperature of the various components of each computer system is not exceeded.
Individual computer systems, such as servers, typically use heat sinks to remove heat from heat generating sources. The heat is then evacuated outside the computer system housing by one or more internal mechanical fans which draw in cooler air from outside the computer system housing and exhaust warmed air through an exhaust vent. Typically computer systems are designed to draw air in through a vent on the front of the system and to exhaust warmed air through a vent in the rear of the system.
When arranged in data centers, computer equipment is generally arranged in racks, with each rack containing multiple items of computer equipment. Data centers also generally use computer room air conditioning units that supply cooled air to the front of the racks and evacuate heated air from the back of the racks.
Accordingly, a significant proportion of the operating cost of a data center can arise from the operation of cooling systems, both within individual computer equipment and at the data center infrastructure level.